This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We are interested in imaging and quantifying the constrast generated by susceptibility variations in the mouse brain at high magnetic field. The work is based on the observations by Duyn et al that cytoarchitectural details of the brain can become much more apparent in phase contrast images than with more traditional contrast metrics (e.g. T1,T2, diffusion). We believe this is a fundamentally enabling project that will allow extension into many different areas. The project has several different phases: Phase 1: We will establish the method for phase contrast imaging based upon work done previously at the Lucas Center (Stanford). This will involve measuring and correcting for Bo inhomogenities in the 7T MR system and measuring and correcting for B1 inhomogeneity of the M2M 35 mm quadrature coil. Phase 2: We will image live C57BL/6J mice using a 3D implementation of the phase contrast method at spatial resolution of <100 microns. We will compare the contrast seen in specific regions of the brain to more traditional imaging protocols (SPGR, FSE, and FIESTA) Phase 3: We will export the method to the 9.4T system to allow imaging of perfusion fixed brains at 21 microns where distribution of the active stain (ProHance) may provide more dramatic phase contrast. Phase 4: We will look toward to possibility of detecting small concentrations of SPIO contrast agent[unreadable]initally in phantoms to determine the potential sensitivity enhancement for molecular imaging.